CA2074015C - Miniature antenna - Google Patents
Miniature antenna Download PDFInfo
- Publication number
- CA2074015C CA2074015C CA002074015A CA2074015A CA2074015C CA 2074015 C CA2074015 C CA 2074015C CA 002074015 A CA002074015 A CA 002074015A CA 2074015 A CA2074015 A CA 2074015A CA 2074015 C CA2074015 C CA 2074015C
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- base portion
- antenna according
- top loop
- approximately
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
- H01Q1/362—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith for broadside radiating helical antennas
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
- H01Q9/32—Vertical arrangement of element
- H01Q9/36—Vertical arrangement of element with top loading
Abstract
A miniature antenna comprises an elongated base portion (10) and an essentially circular top loop (12) that is perpendicular thereto. A U-shaped load (14) is connected between the partially helical (20) base portion (20) and the top loop (12), and its first leg (16) is connected essentially perpendicular to the elongated base portion (10) while its second leg (18) is connected essentially tangential to the top loop (12).
Description
f v.~.;~ f.': ~; n ,.~. s.T::;t MINIATURE ANTENNA
TECHNICAL FIELD
The present invention relates to a miniature antenna, preferably for pocket telephones, comprising a base portion with a longitu-dinal axis and an essentially circular top loop that is essen-tially perpendicular to said axis.
Antennas for pocket telephones usually comprise an antenna rod with a length of a half or a quarter of a wave length.
The half wave antenna has a current distribution in -the foam of half of a sine wave, that is the current is zero at the ends and has a maximum in the middle. This antenna type works well from a technical point of view, but it has the drawback that it is bulky. This is because at the usually used radio frequencies of 15. 900 MHz a wave length of approximately 30 cm is obtained. This means an antenna length of approximately 15 cm, which by many users is considered unpraotical and implies a risk that the antenna will be damaged when the pocket telephone is used.
A quarter wave antenna is half as long, that is 7-$ cm, and is therefore more practical. However, this antenna type has an unfavourable current distribution in the form of a quarter of a sine wave, the current being zero at the top of the antenna and at a maximum at the antenna base.
Furthermore, a circularly polarized antenna comprising an elong-aced base portion and an essentially circular top loop that is perpendicular thereto is known per se from "Antennas", John D.
Kraus, McGraw-Hill.
An object of the present invention is to provide a linearly polarized miniature antenna that further to being short also provides an essentially rectangular current distribution between the point of connection at the antenna base and the antenna top.
SUMMARY OF THE INVENTION
Therefore, in accordance with the present invention there is provided a linearly polarized miniature antenna, comprising: a substantially helical base portion wound around a longitudinal axis and having a length of less than a quarter of a wavelength suitable for cellular communications; a substantially circular top loop arranged perpendicular to the axis and having a larger diameter than the helical base portion; and a substantially U-shaped load connecting the helical base portion to the circular top loop for creating a rectangular current distribution in the antenna, the U-shaped load comprising: a first elongated leg substantially perpendicular to the axis, a second elongated leg substantially perpendicular to the axis, and a bend of approximately 180 degrees connecting the first leg to the second leg so that the legs are substantially parallel to each other.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawing, which shows a preferred embodiment of a miniature antenna in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The miniature antenna in accordance with the present invention comprises a base portion 10 and an essentially 2a circular top loop 12, that is essentially perpendicular to the base portion 10. Top loop 12 comprises at least one, preferably a bit more than one turn.
A U-shaped load 14 is provided between base portion 10 and top loop 12. The first leg 16 of load 14 is connected essentially perpendicular to base portion 10, while its second leg 18 is connected essentially tangential to top loop 12. The U-shaped load 14 increases the current flow to top loop 12. This gives l0 the desired rectangular current distribution.
In the preferred embodiment of the invention shown in the drawing the plane in which the U-shaped load 14 lies is perpendicular to top loop 12. However, it is also possible to provide the U-shaped r', Y'i ~ -~ ..s ~s y'r J /. ~,.~ ~_ n'i' load 14 in a plane that is perpendicular to base portion 10.
Base portion 10 has a helically wound mid portion 20 comprising for instance about 10 turns. In the drawing the helix has uniform diameter.
In an alternate embodiment the diameter of the helix increases towards top loop 12. Near the top loop the diameter of the helix preferably is smaller than the diameter of the top loop. As an example the~helix can comprise 5 turns with an average diameter increasing from 5 mm in the first turn to 6.5 mm in the fifth turn and a pitch of about 3 mm, while the top loop has an average diameter of 9 mm. In this embodiment U-shaped load 14 can be eliminated since the increasing diameter of the helix will perform the reflection-free adaption of base portion 10 to top loop 12.
In a preferred embodiment the whole antenna is formed by a single thread, which from base portion 10 extends into U-shaped load l4 and thereafter into top loop 12.
The miniature antenna is suitably connected to a schematically spawn transmitter/receiver 22, either directly or over a matching circuit comprising for instance a series capacitor 24 and a parallel inductor 30.
Furthermore, a U-shaped metal band 26, forming an antenna apertu-re enlarging and chassis isolating metal grounding plane, can be provided between capacitor 24 and transmitter/receiver 22 at the current feeding point of 'the antenna. Such a band is especially suitable when the apparatus case comprises a metal frame. The purpose of the grounding plane is to decouple the antenna from the metal frame and to increase the antenna aperture. This is especially important for short antennas. By letting a resonant band shaped metal grounding plane with a total electrical length of a half wave length follow the frame structure at a distance of one or a few millimeters and by letting this band have the same 4 ~~ i- f '_.; '.i '-. ;.', or a few millimeters larger width than the frame and by connect-ing the band to the frame only at the antenna connection point, it is possible to avoid curremt induction in the frame. In order to shorten the band it can be folded to form one or several pockets as in shown in the left part of the drawing. Such a pocket has the function of a shortening series inductor. Since the band does not lie directly on the frame, except at the current feeding point, similar pockets are formed also between the frame and the ends of the band. These!pockets should have an electrical length that corresponds to a quarter of a wave length, referred to the mid frequency of the working range of the antenna, i. e. they should have a high input impedance to prevent current from being transferred to the frame. When the band is shortened this becomes possible only by electrically extending the pocket by filling it with a dielectric that compensates for the shortening.
If the antenna is arranged nan-symmetrically as in the drawing the antenna radiation is reduced in the direction towards the closest corner of the apparatus frame. In this case the band can be extended more along the closest frame side to compensate for the radiation reduction.
In a preferred embodiment of the miniature antenna in accordance with the present invention the antenna is embedded in a clielec-tric material, preferably with a dielectric constant of approxi-mately 3, for instance silicone. The dielectric material can for instance be in 'the shape of a frustum of a cone 28, the thicker part of which surrounds elongated base portian 10 and the thinner part of which surrounds U-shaped load 14 and top loop 12. By this embedding in a dielectric material -the antenna can be further shortened and further more be better protected against punches.
At a carrier freguency of approximately 895 MHz the antenna, when combined with an ordinary sized pocket phone, preferably has the fpllowing data:
;~3 '.° ~'v ° '~ ,t ~o.
~ :' ,i ~'.
Antenna length 31.5 mm Thread length (including inductor 30) 130 mm Thread diameter 0.75 mm Number of turns in base portion 11 Outer diameter 3.5 mm Length of wound portion 15.5 mm Number of turns in top loop 1.5 Outer diameter 8.5 mm Length of leg of U-shaped load ~ 7 mm Height of load + top loop 3 mm Length between load and wound portion 3 mm Length between wound portion and pocket phone 10 mm Thread material silver plated copper Dielectric material in cone Sylgard 170 from DOW
CORNING CORP, USA
Cone diameter at top 12 mm Cone diameter a~t base 13 mm Capacitor 47 pf, ceramic Inductor 9 turns, outer die-meter 2,5 mm, thread diameter 0,75 mm It will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departure from the spirit and scope thereof, which is defined by the appended claims. F'or instance the dimensions of the antenna can be changed to make it suitable for other frequen-cies, for instance frequencies around 450 MHz or 1.700 MHz.
TECHNICAL FIELD
The present invention relates to a miniature antenna, preferably for pocket telephones, comprising a base portion with a longitu-dinal axis and an essentially circular top loop that is essen-tially perpendicular to said axis.
Antennas for pocket telephones usually comprise an antenna rod with a length of a half or a quarter of a wave length.
The half wave antenna has a current distribution in -the foam of half of a sine wave, that is the current is zero at the ends and has a maximum in the middle. This antenna type works well from a technical point of view, but it has the drawback that it is bulky. This is because at the usually used radio frequencies of 15. 900 MHz a wave length of approximately 30 cm is obtained. This means an antenna length of approximately 15 cm, which by many users is considered unpraotical and implies a risk that the antenna will be damaged when the pocket telephone is used.
A quarter wave antenna is half as long, that is 7-$ cm, and is therefore more practical. However, this antenna type has an unfavourable current distribution in the form of a quarter of a sine wave, the current being zero at the top of the antenna and at a maximum at the antenna base.
Furthermore, a circularly polarized antenna comprising an elong-aced base portion and an essentially circular top loop that is perpendicular thereto is known per se from "Antennas", John D.
Kraus, McGraw-Hill.
An object of the present invention is to provide a linearly polarized miniature antenna that further to being short also provides an essentially rectangular current distribution between the point of connection at the antenna base and the antenna top.
SUMMARY OF THE INVENTION
Therefore, in accordance with the present invention there is provided a linearly polarized miniature antenna, comprising: a substantially helical base portion wound around a longitudinal axis and having a length of less than a quarter of a wavelength suitable for cellular communications; a substantially circular top loop arranged perpendicular to the axis and having a larger diameter than the helical base portion; and a substantially U-shaped load connecting the helical base portion to the circular top loop for creating a rectangular current distribution in the antenna, the U-shaped load comprising: a first elongated leg substantially perpendicular to the axis, a second elongated leg substantially perpendicular to the axis, and a bend of approximately 180 degrees connecting the first leg to the second leg so that the legs are substantially parallel to each other.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawing, which shows a preferred embodiment of a miniature antenna in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The miniature antenna in accordance with the present invention comprises a base portion 10 and an essentially 2a circular top loop 12, that is essentially perpendicular to the base portion 10. Top loop 12 comprises at least one, preferably a bit more than one turn.
A U-shaped load 14 is provided between base portion 10 and top loop 12. The first leg 16 of load 14 is connected essentially perpendicular to base portion 10, while its second leg 18 is connected essentially tangential to top loop 12. The U-shaped load 14 increases the current flow to top loop 12. This gives l0 the desired rectangular current distribution.
In the preferred embodiment of the invention shown in the drawing the plane in which the U-shaped load 14 lies is perpendicular to top loop 12. However, it is also possible to provide the U-shaped r', Y'i ~ -~ ..s ~s y'r J /. ~,.~ ~_ n'i' load 14 in a plane that is perpendicular to base portion 10.
Base portion 10 has a helically wound mid portion 20 comprising for instance about 10 turns. In the drawing the helix has uniform diameter.
In an alternate embodiment the diameter of the helix increases towards top loop 12. Near the top loop the diameter of the helix preferably is smaller than the diameter of the top loop. As an example the~helix can comprise 5 turns with an average diameter increasing from 5 mm in the first turn to 6.5 mm in the fifth turn and a pitch of about 3 mm, while the top loop has an average diameter of 9 mm. In this embodiment U-shaped load 14 can be eliminated since the increasing diameter of the helix will perform the reflection-free adaption of base portion 10 to top loop 12.
In a preferred embodiment the whole antenna is formed by a single thread, which from base portion 10 extends into U-shaped load l4 and thereafter into top loop 12.
The miniature antenna is suitably connected to a schematically spawn transmitter/receiver 22, either directly or over a matching circuit comprising for instance a series capacitor 24 and a parallel inductor 30.
Furthermore, a U-shaped metal band 26, forming an antenna apertu-re enlarging and chassis isolating metal grounding plane, can be provided between capacitor 24 and transmitter/receiver 22 at the current feeding point of 'the antenna. Such a band is especially suitable when the apparatus case comprises a metal frame. The purpose of the grounding plane is to decouple the antenna from the metal frame and to increase the antenna aperture. This is especially important for short antennas. By letting a resonant band shaped metal grounding plane with a total electrical length of a half wave length follow the frame structure at a distance of one or a few millimeters and by letting this band have the same 4 ~~ i- f '_.; '.i '-. ;.', or a few millimeters larger width than the frame and by connect-ing the band to the frame only at the antenna connection point, it is possible to avoid curremt induction in the frame. In order to shorten the band it can be folded to form one or several pockets as in shown in the left part of the drawing. Such a pocket has the function of a shortening series inductor. Since the band does not lie directly on the frame, except at the current feeding point, similar pockets are formed also between the frame and the ends of the band. These!pockets should have an electrical length that corresponds to a quarter of a wave length, referred to the mid frequency of the working range of the antenna, i. e. they should have a high input impedance to prevent current from being transferred to the frame. When the band is shortened this becomes possible only by electrically extending the pocket by filling it with a dielectric that compensates for the shortening.
If the antenna is arranged nan-symmetrically as in the drawing the antenna radiation is reduced in the direction towards the closest corner of the apparatus frame. In this case the band can be extended more along the closest frame side to compensate for the radiation reduction.
In a preferred embodiment of the miniature antenna in accordance with the present invention the antenna is embedded in a clielec-tric material, preferably with a dielectric constant of approxi-mately 3, for instance silicone. The dielectric material can for instance be in 'the shape of a frustum of a cone 28, the thicker part of which surrounds elongated base portian 10 and the thinner part of which surrounds U-shaped load 14 and top loop 12. By this embedding in a dielectric material -the antenna can be further shortened and further more be better protected against punches.
At a carrier freguency of approximately 895 MHz the antenna, when combined with an ordinary sized pocket phone, preferably has the fpllowing data:
;~3 '.° ~'v ° '~ ,t ~o.
~ :' ,i ~'.
Antenna length 31.5 mm Thread length (including inductor 30) 130 mm Thread diameter 0.75 mm Number of turns in base portion 11 Outer diameter 3.5 mm Length of wound portion 15.5 mm Number of turns in top loop 1.5 Outer diameter 8.5 mm Length of leg of U-shaped load ~ 7 mm Height of load + top loop 3 mm Length between load and wound portion 3 mm Length between wound portion and pocket phone 10 mm Thread material silver plated copper Dielectric material in cone Sylgard 170 from DOW
CORNING CORP, USA
Cone diameter at top 12 mm Cone diameter a~t base 13 mm Capacitor 47 pf, ceramic Inductor 9 turns, outer die-meter 2,5 mm, thread diameter 0,75 mm It will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departure from the spirit and scope thereof, which is defined by the appended claims. F'or instance the dimensions of the antenna can be changed to make it suitable for other frequen-cies, for instance frequencies around 450 MHz or 1.700 MHz.
Claims (11)
1. A linearly polarized miniature antenna, comprising:
a substantially helical base portion wound around a longitudinal axis and having a length of less than a quarter of a wavelength suitable for cellular communications;
a substantially circular top loop arranged perpendicular to said axis and having a larger diameter than said helical base portion; and a substantially U-shaped load connecting said helical base portion to said circular top loop for creating a rectangular current distribution in said antenna, said U-shaped load comprising:
a first elongated leg substantially perpendicular to said axis, a second elongated leg substantially perpendicular to said axis, and a bend of approximately 180 degrees connecting said first leg to said second leg so that said legs are substantially parallel to each other.
a substantially helical base portion wound around a longitudinal axis and having a length of less than a quarter of a wavelength suitable for cellular communications;
a substantially circular top loop arranged perpendicular to said axis and having a larger diameter than said helical base portion; and a substantially U-shaped load connecting said helical base portion to said circular top loop for creating a rectangular current distribution in said antenna, said U-shaped load comprising:
a first elongated leg substantially perpendicular to said axis, a second elongated leg substantially perpendicular to said axis, and a bend of approximately 180 degrees connecting said first leg to said second leg so that said legs are substantially parallel to each other.
2. The antenna according to claim 1, wherein said top loop comprises at least a full turn.
3. The antenna according to claim 1, wherein said helical base portion comprises approximately 10 turns.
4. The antenna according to claim 1, wherein the antenna is embedded in a dielectric material.
5. The antenna according to claim 4, wherein the dielectric material has a dielectric constant of approximately 3.
6. The antenna according to claim 5, wherein the dielectric material has the form of a frustum of a cone having a base section and an apex, wherein said base section of said dielectric material surrounds said base portion of said antenna and said apex surrounds said top loop.
7. The antenna according to claim 6, wherein the antenna has a length on an order of 1/10 of a wavelength suitable for cellular communications.
8. The antenna according to claim 7, wherein the antenna has a length of approximately 30 mm.
9. The antenna according to claim 1, wherein said base portion is connected to a matching circuit which is connected to a transmitter/receiver.
10. The antenna according to claim 2, wherein said top loop comprises approximately 1.5 turns.
11. The antenna according to claim 7, wherein the antenna has a length of approximately 31.5 mm for the frequency range of 825-895 MHz.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9102379A SE468917B (en) | 1991-08-16 | 1991-08-16 | MINIATURE ANTENNA |
| SE9102379-6 | 1991-08-16 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2074015A1 CA2074015A1 (en) | 1993-02-17 |
| CA2074015C true CA2074015C (en) | 2001-02-20 |
Family
ID=20383488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002074015A Expired - Fee Related CA2074015C (en) | 1991-08-16 | 1992-07-16 | Miniature antenna |
Country Status (13)
| Country | Link |
|---|---|
| US (1) | US5592184A (en) |
| EP (1) | EP0528775B1 (en) |
| JP (1) | JP3382972B2 (en) |
| AT (1) | ATE142822T1 (en) |
| AU (1) | AU649866B2 (en) |
| CA (1) | CA2074015C (en) |
| DE (1) | DE69213621T2 (en) |
| FI (1) | FI112725B (en) |
| HK (1) | HK1006608A1 (en) |
| MX (1) | MX9204664A (en) |
| SE (1) | SE468917B (en) |
| SG (1) | SG52224A1 (en) |
| TW (1) | TW223188B (en) |
Families Citing this family (26)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE512062C2 (en) * | 1993-07-14 | 2000-01-17 | Ericsson Ge Mobile Communicat | Method and apparatus for improving the efficiency and bandwidth of an antenna on a portable equipment |
| EP0743699B1 (en) * | 1995-05-17 | 2001-09-12 | Murata Manufacturing Co., Ltd. | Surface mounting type antenna system |
| WO1997018601A1 (en) * | 1995-11-15 | 1997-05-22 | Allgon Ab | Dual band antenna means |
| DE19604034A1 (en) * | 1996-02-05 | 1997-08-07 | Aeg Mobile Communication | Vertical antenna for hand held radio |
| JP3146994B2 (en) * | 1996-08-22 | 2001-03-19 | 株式会社村田製作所 | Antenna and resonance frequency adjusting method thereof |
| JP3047836B2 (en) * | 1996-11-07 | 2000-06-05 | 株式会社村田製作所 | Meander line antenna |
| JP3580654B2 (en) * | 1996-12-04 | 2004-10-27 | 京セラ株式会社 | Common antenna and portable radio using the same |
| US6724738B1 (en) | 1997-02-27 | 2004-04-20 | Motorola Inc. | Method and apparatus for acquiring a pilot signal in a CDMA receiver |
| US6144649A (en) * | 1997-02-27 | 2000-11-07 | Motorola, Inc. | Method and apparatus for acquiring a pilot signal in a CDMA receiver |
| GB2323476B (en) * | 1997-03-20 | 2002-01-16 | David Ganeshmoorthy | Communication antenna and equipment |
| US5933121A (en) * | 1998-04-07 | 1999-08-03 | Harris Corporation | Antenna array for sensing signals on conductors |
| EP0987788A3 (en) * | 1998-09-18 | 2003-04-16 | The Whitaker Corporation | Multiple band antenna |
| US6781549B1 (en) | 1999-10-12 | 2004-08-24 | Galtronics Ltd. | Portable antenna |
| GB2380323B (en) * | 2001-09-29 | 2003-11-05 | Motorola Inc | Antenna for use in radio communications |
| US6914581B1 (en) * | 2001-10-31 | 2005-07-05 | Venture Partners | Focused wave antenna |
| US7292203B2 (en) | 2002-06-12 | 2007-11-06 | Thiss Technologies Pte Ltd. | Helix antenna |
| JP4926702B2 (en) * | 2003-06-25 | 2012-05-09 | ザ・ボード・オブ・ガバナーズ・フォー・ハイヤー・エデュケーション，ステイト・オブ・ロード・アイランド・アンド・プロビデンス・プランテーションズ | System and method for providing a distributed load monopole antenna |
| JP4770497B2 (en) * | 2006-02-03 | 2011-09-14 | 日立電線株式会社 | antenna |
| KR101495107B1 (en) | 2006-06-20 | 2015-02-25 | 인터디지탈 테크날러지 코포레이션 | Methods and system for performing handover in a wireless communication system |
| US7414587B2 (en) * | 2006-09-25 | 2008-08-19 | Shure Acquisition Holdings, Inc. | Antenna in a wireless system |
| TWI355778B (en) * | 2006-11-07 | 2012-01-01 | Wistron Neweb Corp | Portable electronic device with function of receiv |
| EP2489098B1 (en) * | 2009-10-16 | 2015-04-15 | EMS Technologies Canada, Ltd. | Spherical perturbation of an array antenna |
| FR3008550B1 (en) * | 2013-07-15 | 2015-08-21 | Inst Mines Telecom Telecom Bretagne | STOP-TYPE ANTENNA AND ANTENNA STRUCTURE AND ANTENNA ASSEMBLY THEREOF |
| US10931019B1 (en) * | 2015-12-14 | 2021-02-23 | Lockheed Martin Corporation | Helix antenna |
| US10283841B2 (en) | 2016-11-29 | 2019-05-07 | Shure Acquisition Holdings, Inc. | Wireless antenna |
| JP6422552B1 (en) * | 2017-10-11 | 2018-11-14 | 株式会社ヨコオ | Antenna device |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2993204A (en) * | 1958-02-28 | 1961-07-18 | Itt | Two-band helical antenna |
| CH499888A (en) * | 1967-12-15 | 1970-11-30 | Onera (Off Nat Aerospatiale) | Helically wound single conductor antenna of reduced dimensions, and method for its manufacture |
| US4012744A (en) * | 1975-10-20 | 1977-03-15 | Itek Corporation | Helix-loaded spiral antenna |
| US4137534A (en) * | 1977-05-26 | 1979-01-30 | Goodnight Roy G | Vertical antenna with low angle of radiation |
| US4121218A (en) * | 1977-08-03 | 1978-10-17 | Motorola, Inc. | Adjustable antenna arrangement for a portable radio |
| US4161737A (en) * | 1977-10-03 | 1979-07-17 | Albright Eugene A | Helical antenna |
| AU3146384A (en) * | 1984-01-23 | 1985-08-01 | Emil Milan Barkovic | Variable antenna |
| US4697192A (en) * | 1985-04-16 | 1987-09-29 | Texas Instruments Incorporated | Two arm planar/conical/helix antenna |
| CA1257694A (en) * | 1985-08-05 | 1989-07-18 | Hisamatsu Nakano | Antenna system |
| US5216436A (en) * | 1991-05-31 | 1993-06-01 | Harris Corporation | Collapsible, low visibility, broadband tapered helix monopole antenna |
-
1991
- 1991-08-16 SE SE9102379A patent/SE468917B/en not_active IP Right Cessation
-
1992
- 1992-07-16 CA CA002074015A patent/CA2074015C/en not_active Expired - Fee Related
- 1992-07-16 TW TW081105615A patent/TW223188B/zh active
- 1992-07-22 EP EP92850177A patent/EP0528775B1/en not_active Expired - Lifetime
- 1992-07-22 SG SG1996000709A patent/SG52224A1/en unknown
- 1992-07-22 DE DE69213621T patent/DE69213621T2/en not_active Expired - Fee Related
- 1992-07-22 AT AT92850177T patent/ATE142822T1/en not_active IP Right Cessation
- 1992-08-12 FI FI923614A patent/FI112725B/en not_active IP Right Cessation
- 1992-08-12 MX MX9204664A patent/MX9204664A/en not_active IP Right Cessation
- 1992-08-13 JP JP21621792A patent/JP3382972B2/en not_active Expired - Fee Related
- 1992-08-14 AU AU21011/92A patent/AU649866B2/en not_active Ceased
-
1995
- 1995-05-23 US US08/447,344 patent/US5592184A/en not_active Expired - Lifetime
-
1998
- 1998-06-17 HK HK98105584A patent/HK1006608A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| SE468917B (en) | 1993-04-05 |
| ATE142822T1 (en) | 1996-09-15 |
| EP0528775A1 (en) | 1993-02-24 |
| FI923614A (en) | 1993-02-17 |
| FI112725B (en) | 2003-12-31 |
| AU649866B2 (en) | 1994-06-02 |
| CA2074015A1 (en) | 1993-02-17 |
| SE9102379D0 (en) | 1991-08-16 |
| US5592184A (en) | 1997-01-07 |
| DE69213621D1 (en) | 1996-10-17 |
| JP3382972B2 (en) | 2003-03-04 |
| JPH05206715A (en) | 1993-08-13 |
| AU2101192A (en) | 1993-02-18 |
| TW223188B (en) | 1994-05-01 |
| MX9204664A (en) | 1993-02-01 |
| EP0528775B1 (en) | 1996-09-11 |
| SE9102379L (en) | 1993-02-17 |
| HK1006608A1 (en) | 1999-03-05 |
| DE69213621T2 (en) | 1997-02-06 |
| FI923614A0 (en) | 1992-08-12 |
| SG52224A1 (en) | 1998-09-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |